1. Field of the Invention
This invention relates generally to the field of medical devices, and more particularly pertains to the field of catheter guidewire and flushing apparatus.
2. Description of the Prior Art
Peripherally inserted catheters have long been used to access the vascular system because they provide a means of repeated access without causing trauma or pain to the patient. Additionally, when long term vascular access is required (greater then two weeks) a catheter should be used because the alternative, multiple injections, can cause patient discomfort and lead to vein deterioration. When peripheral catheters are installed in a patient's extremity, they are left in the vein and therefore a portion protrudes through the skin for access. These prior art catheters were short (approximately one to one and one-half inches). Their short length results in migration into and out of the vein, an undesired occurrence. This migration provides an opening for infectious agents to enter the vascular system which has led to serious complications. Because of this, peripheral intravascular catheters were usually changed every two to three days. In certain circumstances, they were replaced daily.
Peripherally inserted central catheters, or PICCs, were developed to alleviate some of the problems associated with long-term vascular access using short-term peripheral catheters. The PICC is a much longer catheter designed to be inserted percutaneously such that it reaches deep into the vascular system. The end of the catheter is usually placed in the superior vena cava of the heart to utilize the larger blood volume in that chamber as a diluent for the medication being administered. PICCs are becoming the device of choice for providing access to a patient's vascular system for therapeutic support such as chemotherapy, antibiotic treatment, chemical environment monitoring and intravenous medication.
To place the end of the PICC in the heart, one must be able to navigate the tortuous venous path, which includes many natural blockades (e.g., venous valves). The catheter must be soft and pliable for navigation and comfort. It must also be constructed of biocompatible materials because of the long indwelling period. Catheters having these characteristics are usually manufactured of medical grade polyurethane or silicone rubber, both of which can be made very soft and pliable.
PICC lines made of these soft pliable materials are very difficult and time consuming to install. Their pliant construction allows them to collapse and bend making insertion tedious. Often, it can take up to one hour to insert one catheter, time most clinicians do not have. This also increases the cost of health care.
To ease the difficulty of installation, a flexible metal stylet, or guidewire, is used as a means of stiffening the catheter for insertion. Once the catheter is inserted, the guidewire is removed, leaving the soft, pliable, catheter in the desired position. The two most common guidewire types are of a coiled spring or twist-braided wire construction.
The use of guidewires, however, causes their own problems. A first problem is that friction between the guidewire and catheter inner-wall increases the difficulty of removing the guidewire. The tortuous route the catheter takes in order to reach its final destination causes bends in the catheter guidewire apparatus forcing the guidewire against the inner wall. To reduce this friction, some manufacturers have coated their guidewires with a teflon (PTFE) material, adding some lubricity and thereby reducing the friction between the guidewire and the catheter inner-wall. A second approach to reducing friction is to coat the guidewire with hydrophilic silicone. Such coatings provide lubricating surfaces when they become wet. Both of these methods, which require coating the guidewire, are useful on either the coiled spring or the twist-braided guidewire.
A second problem involved with the use of guidewires is the potential for vessel perforation if the end of the guidewire is forced against the vessel wall. To reduce this danger, coiled spring wires use a soft flexible tip while twist-braided wires have a spherical ball affixed to their ends.
No matter what type of guidewire is used, it is recommended that the catheter be flushed with an aqueous solution before, during, and after catheter insertion. The catheter guidewire apparatus is flushed prior to patient installation in order to check for catheter patency. The catheter is flushed during installation to help maneuver it through the tortuous venous path and to prevent blood from entering the PICC and clotting (an occurrence which makes guidewire removal difficult or impossible). The catheter is flushed after installation in order to facilitate removal of the guidewire. Therefore, there is a need for an apparatus that allows for safe, convenient and economical flushing of catheter guidewire systems before, during and after insertion.
Prior art catheter guidewire apparatus' recommended that the user install the guidewire so that it emerges a little, approximately one-half of one centimeter beyond the end of the catheter. This is for flushing purposes and to provide the user with a portion to hold when removing the guidewire. Traditionally, when flushing a catheter that has a guidewire installed therein, a syringe is connected to the catheter by placing the exposed portion of the guidewire into the tip of the syringe and fastening the syringe to the catheter's fitting. While this method provides a way to supply liquid a interface between the catheter and the guidewire, it has several disadvantages. With this method, the exposed portion of the guidewire is actually inserted inside the syringe's barrel. During flushing, the syringe's plunger naturally moves further into the barrel. A major disadvantage of this system is that the depressing plunger is prone to striking that portion of the guidewire that is within the syringe's barrel. In such a situation, the plunger then may push the guidewire further into the catheter causing the guidewire to actually emerge from the end of the catheter that is deep within a patient. When this occurs, the guidewire, which is now exposed in the patient, can puncture vital organs of the patient such as a lung or a major vein.
This traditional method also does not work well when the catheter is trimmed to length (catheters are made to standard lengths which may be longer than needed to ensure that the tip is installed at the most desirable site). Since the guidewire has a special tip on its end, as discussed above, it is usually not cut and therefore the guidewire must be partially withdrawn prior to trimming. In this situation, there will be considerably more than the normal length of guidewire emerging from the end of the catheter. This excess length of guidewire cannot be inserted in the syringe barrel, thereby preventing the syringe from being placed over the syringe's female luer for flushing. This is a major disadvantage of the prior art.
Some manufacturers suggest that post-catheter shortening flushing when excess guidewire emerges from the female hub can be accomplished by forcing the syringe tip alongside the wire in the end of the catheter, thereby bending the guidewire to the side of the catheter end. A major disadvantage to forcing the syringe in the catheter's end with the guidewire bent away from the syringe's luer is that in such an arrangement there will be no seal between the catheter and the syringe. An incomplete seal will lead to leaks which will prevent adequate flushing. Therefore, since prior art devices are extremely difficult to flush once the catheter has been shortened, guidewire removal, which is a critical requirement of catheter guidewire systems, has been very difficult and a better system and method is needed.
The present invention overcomes the problems associated with prior art catheter guidewire flushing apparatus. The invention allows the user to flush the catheter before using it to check catheter patency, to flush the catheter during insertion to help maneuver around venous obstructions, to flush the catheter after placement for guidewire removal, to leave the guidewire in place to help visibility when checking placement position radio graphically and to be able to trim a catheter and still maintain a seal between a syringe and the catheter.